A convenient synthesis of 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines via Pictet-Spengler reaction using titanium(IV) isopropoxide and acetic-formic anhydride.
نویسندگان
چکیده
A synthesis of 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines (6) was achieved in a highly efficient manner via Pictet-Spengler reaction of arylethylamines (1) and acyclic and cyclic ketones (2) using titanium (IV) isopropoxide and acetic-formic anhydride. The cyclization of the in situ formed acyliminium ion (4) to N-formyl 1,2,3,4-tetrahydroisoquinoline (5) was greatly facilitated by using trifluoroacetic acid as an additional reagent. The Pictet-Spengler reaction was carried out by one pot procedure, providing a convenient and effective method for preparing various 1,2,3,4-tetrahydroisoquinolines.
منابع مشابه
Enzyme catalysed Pictet-Spengler formation of chiral 1,1'-disubstituted- and spiro-tetrahydroisoquinolines
The Pictet-Spengler reaction (PSR) involves the condensation and ring closure between a β-arylethylamine and a carbonyl compound. The combination of dopamine and ketones in a PSR leads to the formation of 1,1'-disubstituted tetrahydroisoquinolines (THIQs), structures that are challenging to synthesize and yet are present in a number of bioactive natural products and synthetic pharmaceuticals. H...
متن کاملSynthesis and contractile activity of substituted 1,2,3,4-tetrahydroisoquinolines.
A series of different 1-monosubstituted and 1,1-disubstituted 1,2,3,4-tetrahydro-isoquinolines was synthesized in high yields from different ketoamides. We have developed a convenient method for the synthesis of disubstituted derivatives by interaction of ketoamides with organomagnesium compounds, followed by cyclization in the presence of catalytic amounts of p-toluenesulfonic acid (PTSA). A n...
متن کاملthrinan, homoerythrinan, isopavine and pavine alkaloids using an aromatic cyclization of the sulfonium ion in situ
tetrahydroisoquinolines, 1,2,3,4-tetrahydroquinolines, 2,3,4,5-tetrahydro-1H-3-benzazepines, 2-quinolones, erythrinan, homoerythrinan, isopavine and pavine alkaloids using an aromatic cyclization of the sulfonium ion in situ formed from a sulfinyl precursor (Pummerer reaction). The aromatic cyclization in the reaction using trifluoroacetic anhydride (TFAA) smoothly proceeded at room temperature...
متن کاملSynthesis of 1-substituted 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-diones.
1,2-Disubstituted 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-diones are prepared for the first time through an activated Pictet-Spengler reaction of the corresponding imines of 2-(1,4-dimethoxynaphth-2-yl)ethylamine in the presence of an acyl chloride and AlCl(3) followed by an oxidation with silver(II) oxide in nitric acid. Depending on the reaction conditions the N-trichloroacetyl protecting ...
متن کاملPreparation of Carboxylato-Coordinated Titanium Alkoxides from Carboxylic Anhydrides: Alkoxido Group Transfer from Metal Atom to Carbonyl Group
Reaction of titanium(IV) isopropoxide, Ti(OiPr)4, with an equimolar amount of phthalic anhydride resulted in the transfer of an isopropoxido group from the metal atom to one carbonyl group of the anhydride and coordination of the thus formed monoester to the titanium atom. One monoester ligand in Ti2(OiPr)6(μ2-OOC-C6H4-COOiPr)(η1-OOC-C6H4-COOiPr)(iPrOH) is bridging and the other is η1-coordinat...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemical & pharmaceutical bulletin
دوره 50 2 شماره
صفحات -
تاریخ انتشار 2002